TAP2

Chr 6p21.32

transporter 2, ATP binding cassette subfamily B member

Aliases:: PSF2, RING11, D6S217E
MANE:: ENST00000374897.4

OMIM: 170261 ↗NCBI: 6891 ↗Ensembl ↗

Annotations refreshed 9 hours ago.

Predicted protein structure

AlphaFold predicted structure

TAP2 · Q03519

v62025-08-01

Predicted Aligned Error matrix for TAP2 — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

82.7/ 100

Confident

686 residues

Confidence breakdown

Very high(≥ 90)38%
Confident(70–90)42%
Low(50–70)18%
Very low(< 50)2%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

COVID-19 research
BIALLELIC, autosomal or pseudoautosomal
Primary immunodeficiency or monogenic inflammatory bowel disease
BIALLELIC, autosomal or pseudoautosomal

Disease associations (Open Targets)

MHC class I deficiency
0.71
Immunodeficiency by defective expression of HLA class 1
0.60
MHC class I deficiency 2
0.48
hereditary disease
0.19
neoplasm
0.10
cancer
0.10
tuberculosis
0.09
cervical carcinoma
0.09
cervical cancer
0.08
non-small cell lung carcinoma
0.08

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Antigen peptide transporter 2

ABC transporter associated with antigen processing. In complex with TAP1 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (PubMed:25377891, PubMed:25656091). Uses the chemical energy of ATP to export peptides against the concentration gradient (PubMed:25377891). During the transport cycle alternates between 'inward-facing' state with peptide binding site facing the cytosol to 'outward-facing' state with peptide binding site facing the ER lumen. Peptide antigen binding to ATP-loaded TAP1-TAP2 induces a switch to hydrolysis-competent 'outward-facing' conformation ready for peptide loading onto nascent MHCI molecules. Subsequently ATP hydrolysis resets the transporter to the 'inward facing' state for a new cycle (PubMed:11274390, PubMed:25377891, PubMed:25656091). Typically transports intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via IFNG-induced immunoproteasome. Binds peptides with free N- and C-termini, the first three and the C-terminal residues being critical. Preferentially selects peptides having a highly hydrophobic residue at position 3 and hydrophobic or charged residues at the C-terminal anchor. Proline at position 2 has the most destabilizing effect (PubMed:11274390, PubMed:7500034, PubMed:9256420). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (PubMed:1538751, PubMed:25377891, PubMed:26611325)